Neem seeds, oil, leaves and twig sap have been used for medicinal and therapeutic purposes in treating or preventing ailments relating to the alimentary canal, ulcers, diabetes, skin, gums, teeth and hair. The neem leaves, when mixed with earth mortar, have been used in flooring and plastering of walls containing twigs and vines that act as reinforcement. The leaves have been known to protect the organically rich soil and the reinforcement for a considerable amount of time.
With the isolation of azadirachtin from the oil of neem seeds, it has been observed that azadirachtin--a tetranortriterpenoid having a molecular weight of 720.23--is the active ingredient that is a highly effective insect feeding deterrent. Various neem seed extracts, particularly those containing azadirachtin, are now known to influence the feeding behavior, growth regulation, and fecundity of numerous species of insects and fungi. Currently, azadirachtin is being investigated for prospective use as a biodegradable, non-toxic pesticide.
The prior art is replete with teachings of azadirachtin or azadirachtin-containing neem extracts, and methods of preparing the same, for use as pesticides. Azadirachtin and azadirachtin-containing neem extracts are desirable as pesticides in that they are non-toxic to humans and the environment. What is currently lacking in this art is ways in which to expand the uses of this environmentally safe, non-toxic insecticide.
Heretofore, for example, the use of neem extracts in compositions suitable for protecting wood and other cellulosic materials from infestation and destruction by termites, wood borers and other insects is unknown in the art.
Moreover, it is heretofore unknown in the art to use neem leaf paste in a composition suitable for protecting and preserving wood and other cellulosic materials from infestation and destruction by termites, wood borers and other insects.
Another shortcoming of azadirachtin is its stability i.e., it has a relatively short shelf life. The prior art discloses various attempts at retarding the degradation of azadirachtin. These prior art attempts typically involve extraction of the azadirachtin through the use of solvents at elevated temperatures and/or pressures. The current invention and applications preserve the efficacy of azadirachtin and avoid the precursors to degradation which result in loss of efficacy.
The invention preserves the efficacy of the azadirachtin in the neem plant extract by adding preservative, binding agents, in quantities above that naturally present in the neem plant extracts. These binding agents, lignins and tannins, are used individually or in combination to preserve the azadirachtin.
Lignin is a natural phenolic polymerie substance that is found in the cell walls of plant material. Lignin is extremely resistant to chemical and enzymic degradation, and it is not soluble in ordinary solvents unless it is degraded. Consequently, lignin is not readily biodegradable, impedes lytic actions of solvents in a wide range of pH levels, and provides corrosion resistance properties.
The melting point of lignin is measured around 250-275.degree. Celsius, depending on the contact isomers. Lignins formed from the soda process, a common process in the field, are observed to have a lower melting range and offer better flow properties. Calcium lignosulfonate, a lignin derivative, is capable of polymerization under heat, which makes it useful in autoclaving for the cementing of the penetrated compositions and/or mixtures.
Tannin is a generic name for a family of weak polyphenolic acids that occur in the bark, woody tissues, and leaves of certain plants. In plants, tannins are believed to provide resistance to disease by binding to and reducing the availability of proteins in damaged plant tissue. Tannins tend to polymerize into insoluble compounds. There are two main types of tannins, namely pyrogallol tannins and catechol tannins. Catechol tannins exhibit significantly higher resistance to heat and decay than the pyrogallol tannins. Thus, catechol tannins have been used to protect fishing nets, sails, and leather goods against rotting and degrading under wet weathering.
Heretofore, the use of neem extracts in combination with additive concentrations of lignin or tannins for any purpose is unknown in the art, and in particular for protecting wood composites and other cellulosic materials from infestation and destruction by termites, wood borers and other insects. The additive quantities of Lignin and Tannin far exceed the naturally occurring quantities the neem plant or any other wood. The prior art does not teach the use of these components in combination for the preservation of wood composites and other cellulosic materials. The synergistic effects of these components used in combination are multiple, namely:
a) The broader antimicrobicidal activity; PA1 b) The prolonged effective shelf and active life; PA1 c) The improvement of basic properties, viz a viz, adhesion and water resistance. PA1 1) classifying and de-matting neem leaves in bundles (leaves used for this purpose should be of a moisture content of not less than the critical moisture content); PA1 2) washing and straining to remove dirt, rocks and other inert matter; PA1 3) crushing and grinding to open up the effective surface area of the active plant material; PA1 4) wet milling; PA1 5) straining; and PA1 6) homogenizing with neem oil and an emulsifier.
The compositions described are applicable to softwood lumber and plywood for use in light commercial and residential foundations. The compositions work within the confines of the basic material and construction requirements, which are found in the design and fabrication of permanent wood foundation systems. The compositions offer coating, encapsulation, covering, barrier formation and preservation functions aside from the functions of the medium transporting the composition, i.e., paint, stain, caulk, or paste.
The compositions may be applied on foundation quality softwood lumber such as Fir, Pine, Ponderosa Pine, Red Pine, Western Hemlock and plywoods composed of softwood plies with exterior glue. For pressure treating lumber, the necessary preconditioning procedures may be carried out with the compositions.
These compositions are novel through their unique selection and combination of ingredients. No other combination disclosed in the prior art has achieved the qualities that the presently disclosed combinations have achieved, i.e. water resistance, resistance to oxidation and ozonation, resistance to UV and photo degradation, and a long effective life.